Textile and surface treatment agents and/or cosmetic agents mostly contain fragrance substances (odorant substances) which impart a pleasant and fresh odor to the agents. The terms odorant substances and fragrance substances are used synonymously in this invention. The fragrance substances usually mask the inherent fragrance note of the other ingredients so that the user has a positive odor impression. Fragrance substances are especially important ingredients of the composition in the field of washing agents because laundry should have a fresh and pleasant fragrance when damp as well as when dry. There is a fundamental problem in the use of fragrance substances in that these are volatile substances; otherwise no fragrance effect could be achieved. However, one strives to achieve the most uniform and long-lasting fragrance effect possible. For example, it is known that the fragrance impression of a perfume changes over a period of time because the odorant substances, which represent the fresh and light notes of the perfume, evaporate more quickly due to their high vapor pressure than the fragrance substances representing heart notes and base notes.
One approach toward solving this problem, namely achieving the most uniform and long-lasting fragrance effect, consists of applying fragrance substances to carrier materials and coating the fragranced carriers or encapsulating fragrance substances or incorporating them into compounds (for example, cyclodextrin perfume complexes). In addition, there is the option of chemically binding the fragrance substances to carrier media, so that the chemical bond is cleaved slowly, thereby releasing the fragrance substance. Such a carrier-bound precursor of a fragrance substance is also referred to as a “pro-fragrance” or a fragrance storage substance. In this context, International Patent Application WO 2007/087977 discloses the use of 1-aza-3,7-dioxabicyclo[3.3.0]octane compounds as fragrance storage substances for delayed release of fragrance aldehydes and fragrance ketones by hydrolysis. An alternative option for delayed release of fragrance substances is to use so-called photoactivatable substances as fragrance storage substances. Breaking of a covalent bond in the molecule of the fragrance storage substance is induced by exposure to sunlight or some other electromagnetic radiation source of a certain wavelength, thereby releasing the fragrance substance. The process described here must tolerate the presence of oxygen and water for effective release of the fragrance substance.
In this context, U.S. Pat. No. 6,949,680 discloses the use of certain phenyl or pyridyl ketones as photoactivatable substances, which release a terminal alkene as an active substance in the presence of light in a photochemical fragmentation. The aforementioned active substance has a fragrancing or antimicrobial activity, for example, which is delayed by the photochemically induced decomposition and is released over a rather long period of time on a certain surface. The aforementioned photolabile phenyl or pyridyl ketones are produced as fragrance storage substances in a complex multistep synthesis process using protective group orientations, wherein the synthesis must be adapted individually for each individual active substance.
In spite of the advances in the prior art, there is an ongoing need to enable a delayed release of fragrance aldehyde (odorant aldehydes) and fragrance ketones (odorant ketones).